1. Field of the Invention
The present invention relates to a handle stem and a speed indicator for bicycles.
2. Description of the Background Art
FIG. 6 shows a front part of a conventional bicycle. On an end of a forward-projecting part of a handle stem 120 of this bicycle, a handle bar 138 is held. At a position which is located on the upper surface of the forward-projecting part of handle stem 120 and is readily visible from the rider, an indicator-housing recess 134 is provided, and an indicator 135 indicating the speed and the like is fit in this indicator-housing recess 134. A lead 149 extending from the indicator passes through a hollow longitudinal rod 121 and a head tube 107 for example to be connected to a sensor 116. Sensor 116 is formed of a device sensing a magnetic field and thus senses a magnetic flux when a small permanent magnet 115 turns to pass near sensor 116. Although lead 149 passes through within longitudinal rod 121 in order not to be visible from the outside, lead 149 may be wound around head tube 107 so as to be visible from the outside.
FIG. 7 is a cross-sectional view along line VII—VII in FIG. 6. Handle stem 120 as shown includes hollow longitudinal rod 121 having its lower part inserted into the head tube of the bicycle, forward-projecting part 122 extending forward from the upper end of longitudinal rod 121, and a handle-bar holding part 123 provided at the front end of forward-projecting part 122. Handle-bar holding part 123 has a through hole 139 for passing handle bar 138 therethrough, so that handle bar 138 can be passed through the through hole 139 to be fixed to forward-projecting part 122 of handle stem 120.
Handle stem 120 has an insert member 124 which is inserted through the lower end of longitudinal rod 121 and moved upward so as to fix longitudinal rod 121 to a front fork stem of the bicycle. Handle stem 120 further has a lifting rod 126 extending through longitudinal rod 121 and insert member 124 for moving insert member 124 upward.
Insert member 124 which is screwed onto an external thread of the lifting rod engages with the lifting rod and longitudinal rod 121 in such a manner that the lifting rod is not easily rotated. Rotation of the lifting rod thus causes the insert member to move upward and accordingly expand the lower end of the longitudinal rod. Then, the longitudinal rod has the expanded lower end with the outer surface accordingly opened and is thus fixed to the front fork stem.
Forward-projecting part 122 is preferably flat-shaped and has its upper surface provided with recess 134. Indicator 135 indicating the speed and the like is housed in this recess 134. The lower surface of recess 134 has a fixing hole 136 which passes therethrough to reach the lower surface of forward-projecting part 122. Fixing hole 136 is used for fixing indicator 135 to recess 134. Specifically, as shown in FIG. 7, a fixing screw 137 is inserted into fixing hole 136 from below forward-projecting part 122 and screwed in an internal thread on the bottom wall of the indicator. The fixing screw is thus screwed to fix the indicator to recess 134.
Indicator 135 has its body in which a battery is housed for supplying electric power for a liquid-crystal display and a semiconductor device performing various operations. Lead 149 drawn from the indicator is passed through a through hole made along the axis of the lifting rod and connected via a connector in the head tube (not shown) for example to a lead extended from the sensor of a speedometer or the like.
With the above-discussed structure, the rider can check the speed, the traveled distance and the like that are indicated on the indicator while riding the bicycle.
The conventional indicator described above, however, requires such tools as driver and spanner for detaching the indicator. The rider normally rides a bicycle without carrying such tools. Therefore, the place where attachment/detachment of the indicator is done for replacement of the battery for example is limited to a particular place. Moreover, if the rider carries tools, the total weight increases which is not preferable for running of the bicycle. In addition, in order to detach the indicator, the whole of the indicator has to be detached from the handle stem without exception. If the entire indicator is detached each time the battery is replaced, the detachment should frequently be done, resulting in a higher possibility of occurrence of break and contact failure of the lead.